CVE-2026-110880 in Kit Plugin
Summary
by MITRE • 10/18/2026
Missing Authorization vulnerability in Kit Kit (formerly ConvertKit) convertkit allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Kit (formerly ConvertKit): from n/a through 3.4.6.
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Analysis
by VulDB Data Team • 10/18/2026
The identified security flaw represents a critical failure in access control mechanisms within the Kit platform, formerly known as ConvertKit, specifically affecting versions ranging from initial releases up to version 3.4.6. This vulnerability is classified under CWE-285, which denotes Improper Authorization, and aligns with MITRE ATT&CK technique T1078, Valid Accounts, where attackers leverage legitimate credentials or misconfigured permissions to gain unauthorized access. The core technical issue stems from an incorrectly configured security level that fails to properly validate user privileges before granting access to sensitive resources or administrative functions. In a typical web application architecture, authorization checks are designed to ensure that the authenticated entity has explicit permission for the requested action based on their role and identity. However, in this instance, the system logic bypasses these essential verification steps, allowing any authenticated user, regardless of their assigned privilege level, to perform actions reserved exclusively for administrators or higher-privileged roles.
The operational impact of this vulnerability is severe, as it effectively nullifies the principle of least privilege that underpins secure application design. An attacker who obtains valid credentials for a low-level account can exploit this misconfiguration to escalate privileges and access restricted areas of the platform. This could lead to unauthorized modification or deletion of subscriber data, manipulation of email campaign configurations, exposure of personal identifiable information belonging to customers, and potential compromise of integrated third-party services linked within the application environment. Since Kit serves as a marketing automation tool handling vast amounts of user-generated content and communication logs, the breach of integrity and confidentiality poses significant risks not only to individual users but also to their respective businesses relying on the platform for customer engagement strategies.
From a technical perspective, this flaw likely originates from server-side logic that relies solely on client-supplied data or session tokens without performing robust backend authorization checks against a centralized access control policy database. The absence of strict object-level and function-level permission verification allows attackers to craft specific HTTP requests targeting administrative endpoints directly. This type of vulnerability is particularly dangerous because it does not require complex exploitation techniques such as buffer overflows or injection attacks; instead, it exploits the fundamental trust model assumed by the application developers regarding user roles. Consequently, even users with minimal intended access can traverse into privileged domains simply by manipulating request parameters to target protected resources that should be inaccessible to their account tier.
Mitigation strategies must prioritize immediate remediation of the underlying code logic responsible for these authorization checks. Developers need to implement rigorous server-side validation for every action involving sensitive data or administrative controls, ensuring that each request is explicitly verified against the user's current role and permissions before execution. This involves adopting a deny-by-default approach where access is only granted if an explicit allow rule exists in the security policy. Additionally, implementing comprehensive logging and monitoring of authorization failures can help detect attempted exploitation patterns early. For organizations still running affected versions, upgrading to version 3.4.7 or later is imperative as it contains patches addressing these specific access control deficiencies. Until updates are applied, administrators should enforce strict network-level restrictions on administrative interfaces and review audit logs for anomalous activity indicative of privilege escalation attempts through this vector.